<?php
if(!defined('IN_WOGU')) {
    exit('Access Denied');
}

class Db_Mysql implements Db_Interface
{

    /**
    * 数据库配置信息
    */
    public $config = null;

    /**
    * 数据库连接资源句柄
    */
    public $link = null;

    /**
    * 最近一次查询资源句柄
    */
    public $lastqueryid = null;

    /**
    *  统计数据库查询次数
    */
    public $querycount = 0;

    public function __construct() {}

    /**
    * 打开数据库连接,有可能不真实连接数据库
    * @param $config    数据库连接参数
    *
    * @return void
    */
    public function open($config) {
        $this->config = $config;
        if($config['autoconnect'] == 1) {
            $this->connect();
        }
    }

    /**
    * 真正开启数据库连接
    *
    * @return void
    */
    public function connect() {
        $func = $this->config['pconnect'] == 1 ? 'mysql_pconnect' : 'mysql_connect';
        if(!$this->link = @$func($this->config['hostname'], $this->config['username'], $this->config['password'], 1)) {
            $this->halt('Can not connect to MySQL server');
            return false;
        }

        if($this->version() > '4.1') {
            $charset = isset($this->config['charset']) ? $this->config['charset'] : '';
            $serverset = $charset ? "character_set_connection='$charset',character_set_results='$charset',character_set_client=binary" : '';
            $serverset .= $this->version() > '5.0.1' ? ((empty($serverset) ? '' : ',')." sql_mode='' ") : '';
            $serverset && mysql_query("SET $serverset", $this->link);
        }

        if($this->config['database'] && !@mysql_select_db($this->config['database'], $this->link)) {
            $this->halt('Cannot use database '.$this->config['database']);
            return false;
        }
        $this->database = $this->config['database'];
        return $this->link;
    }

    /**
    * 数据库查询执行方法
    * @param $sql 要执行的sql语句
    * @return 查询资源句柄
    */
    private function execute($sql) {
        if(!is_resource($this->link)) {
            $this->connect();
        }

        $this->lastqueryid = mysql_query($sql, $this->link) or $this->halt(mysql_error(), $sql);

        $this->querycount++;
        return $this->lastqueryid;
    }

    /**
    * 执行sql查询
    * @param $data         需要查询的字段值[例`name`,`gender`,`birthday`]
    * @param $table         数据表
    * @param $where         查询条件[例`name`='$name']
    * @param $limit         返回结果范围[例：10或10,10 默认为空]
    * @param $order         排序方式    [默认按数据库默认方式排序]
    * @param $group         分组方式    [默认为空]
    * @param $key             返回数组按键名排序
    * @return array        查询结果集数组
    */
    public function select($data, $table, $where = '', $limit = '', $order = '', $group = '', $key = '') {
        $where = $where == '' ? '' : ' WHERE '.$where;
        $order = $order == '' ? '' : ' ORDER BY '.$order;
        $group = $group == '' ? '' : ' GROUP BY '.$group;
        $limit = $limit == '' ? '' : ' LIMIT '.$limit;
        $field = explode(',', $data);
        array_walk($field, array($this, 'add_special_char'));
        $data = implode(',', $field);

        $sql = 'SELECT '.$data.' FROM `'.$this->config['database'].'`.`'.$table.'`'.$where.$group.$order.$limit;
        $this->execute($sql);
        if(!is_resource($this->lastqueryid)) {
            return $this->lastqueryid;
        }

        $datalist = array();
        while(($rs = $this->fetch_next()) != false) {
            if($key) {
                $datalist[$rs[$key]] = $rs;
            } else {
                $datalist[] = $rs;
            }
        }
        $this->free_result();
        return $datalist;
    }

    /**
    * 获取单条记录查询
    * @param $data         需要查询的字段值[例`name`,`gender`,`birthday`]
    * @param $table         数据表
    * @param $where         查询条件
    * @param $order         排序方式    [默认按数据库默认方式排序]
    * @param $group         分组方式    [默认为空]
    * @return array/null    数据查询结果集,如果不存在，则返回空
    */
    public function get_one($data, $table, $where = '', $order = '', $group = '') {
        $where = $where == '' ? '' : ' WHERE '.$where;
        $order = $order == '' ? '' : ' ORDER BY '.$order;
        $group = $group == '' ? '' : ' GROUP BY '.$group;
        $limit = ' LIMIT 1';
        $field = explode( ',', $data);
        array_walk($field, array($this, 'add_special_char'));
        $data = implode(',', $field);

        $sql = 'SELECT '.$data.' FROM `'.$this->config['database'].'`.`'.$table.'`'.$where.$group.$order.$limit;
        $this->execute($sql);
        $res = $this->fetch_next();
        $this->free_result();
        return $res;
    }

    /**
    * 遍历查询结果集
    * @param $type        返回结果集类型
    *                     MYSQL_ASSOC，MYSQL_NUM 和 MYSQL_BOTH
    * @return array
    */
    public function fetch_next($type=MYSQL_ASSOC) {
        $res = mysql_fetch_array($this->lastqueryid, $type);
        if(!$res) {
            $this->free_result();
        }
        return $res;
    }

    /**
    * 释放查询资源
    * @return void
    */
    public function free_result() {
        if(is_resource($this->lastqueryid)) {
            mysql_free_result($this->lastqueryid);
            $this->lastqueryid = null;
        }
    }

    /**
    * 直接执行sql查询
    * @param $sql                            查询sql语句
    * @return    boolean/query resource        如果为查询语句，返回资源句柄，否则返回true/false
    */
    public function query($sql) {
        return $this->execute($sql);
    }

    /**
    * 执行添加记录操作
    * @param $data         要增加的数据，参数为数组。数组key为字段值，数组值为数据取值
    * @param $table         数据表
    * @return boolean
    */
    public function insert($data, $table, $return_insert_id = false, $replace = false) {
        if(!is_array( $data ) || $table == '' || count($data) == 0) {
            return false;
        }

        $fielddata = array_keys($data);
        $valuedata = array_values($data);
        array_walk($fielddata, array($this, 'add_special_char'));
        array_walk($valuedata, array($this, 'escape_string'));

        $field = implode (',', $fielddata);
        $value = implode (',', $valuedata);

        $cmd = $replace ? 'REPLACE INTO' : 'INSERT INTO';
        $sql = $cmd.' `'.$this->config['database'].'`.`'.$table.'`('.$field.') VALUES ('.$value.')';
        $return = $this->execute($sql);
        return $return_insert_id ? $this->insert_id() : $return;
    }

    /**
    * 获取最后一次添加记录的主键号
    * @return int
    */
    public function insert_id() {
        return mysql_insert_id($this->link);
    }

    /**
    * 执行更新记录操作
    * @param $data         要更新的数据内容，参数可以为数组也可以为字符串，建议数组。
    *                         为数组时数组key为字段值，数组值为数据取值
    *                         为字符串时[例：`name`='phpcms',`hits`=`hits`+1]。
    *                        为数组时[例: array('name'=>'phpcms','password'=>'123456')]
    *                        数组可使用array('name'=>'+=1', 'base'=>'-=1');程序会自动解析为`name` = `name` + 1, `base` = `base` - 1
    * @param $table         数据表
    * @param $where         更新数据时的条件
    * @return boolean
    */
    public function update($data, $table, $where = '') {
        if($table == '' or $where == '') {
            return false;
        }

        $where = ' WHERE '.$where;
        $field = '';
        if(is_string($data) && $data != '') {
            $field = $data;
        } elseif (is_array($data) && count($data) > 0) {
            $fields = array();
            foreach($data as $k=>$v) {
                switch (substr($v, 0, 2)) {
                    case '+=':
                    $v = substr($v,2);
                    if (is_numeric($v)) {
                        $fields[] = $this->add_special_char($k).'='.$this->add_special_char($k).'+'.$this->escape_string($v, '', false);
                    } else {
                        continue;
                    }

                    break;
                    case '-=':
                    $v = substr($v,2);
                    if (is_numeric($v)) {
                        $fields[] = $this->add_special_char($k).'='.$this->add_special_char($k).'-'.$this->escape_string($v, '', false);
                    } else {
                        continue;
                    }
                    break;
                    default:
                    $fields[] = $this->add_special_char($k).'='.$this->escape_string($v);
                }
            }
            $field = implode(',', $fields);
        } else {
            return false;
        }

        $sql = 'UPDATE `'.$this->config['database'].'`.`'.$table.'` SET '.$field.$where;
        return $this->execute($sql);
    }

    /**
    * 执行删除记录操作
    * @param $table         数据表
    * @param $where         删除数据条件,不充许为空。
    *                         如果要清空表，使用empty方法
    * @return boolean
    */
    public function delete($table, $where) {
        if ($table == '' || $where == '') {
            return false;
        }
        $where = ' WHERE '.$where;
        $sql = 'DELETE FROM `'.$this->config['database'].'`.`'.$table.'`'.$where;
        return $this->execute($sql);
    }

    /**
    * 获取最后数据库操作影响到的条数
    * @return int
    */
    public function affected_rows() {
        return mysql_affected_rows($this->link);
    }

    /**
    * 获取数据表主键
    * @param $table         数据表
    * @return array
    */
    public function get_primary($table) {
        $this->execute("SHOW COLUMNS FROM $table");
        while($r = $this->fetch_next()) {
            if($r['Key'] == 'PRI') break;
        }
        return $r['Field'];
    }

    /**
    * 获取表字段
    * @param $table         数据表
    * @return array
    */
    public function get_fields($table) {
        $fields = array();
        $this->execute("SHOW COLUMNS FROM $table");
        while($r = $this->fetch_next()) {
            $fields[$r['Field']] = $r['Type'];
        }
        return $fields;
    }

    /**
    * 检查不存在的字段
    * @param $table 表名
    * @return array
    */
    public function check_fields($table, $array) {
        $fields = $this->get_fields($table);
        $nofields = array();
        foreach($array as $v) {
            if(!array_key_exists($v, $fields)) {
                $nofields[] = $v;
            }
        }
        return $nofields;
    }

    /**
    * 检查表是否存在
    * @param $table 表名
    * @return boolean
    */
    public function table_exists($table) {
        $tables = $this->list_tables();
        return in_array($table, $tables) ? 1 : 0;
    }

    public function list_tables() {
        $tables = array();
        $this->execute("SHOW TABLES");
        while($r = $this->fetch_next()) {
            $tables[] = $r['Tables_in_'.$this->config['database']];
        }
        return $tables;
    }

    /**
    * 检查字段是否存在
    * @param $table 表名
    * @return boolean
    */
    public function field_exists($table, $field) {
        $fields = $this->get_fields($table);
        return array_key_exists($field, $fields);
    }

    public function num_rows($sql) {
        $this->lastqueryid = $this->execute($sql);
        return mysql_num_rows($this->lastqueryid);
    }

    public function num_fields($sql) {
        $this->lastqueryid = $this->execute($sql);
        return mysql_num_fields($this->lastqueryid);
    }

    public function result($sql, $row) {
        $this->lastqueryid = $this->execute($sql);
        return @mysql_result($this->lastqueryid, $row);
    }

    public function error() {
        return @mysql_error($this->link);
    }

    public function errno() {
        return intval(@mysql_errno($this->link)) ;
    }

    public function version() {
        if(!is_resource($this->link)) {
            $this->connect();
        }
        return mysql_get_server_info($this->link);
    }

    public function close() {
        if (is_resource($this->link)) {
            @mysql_close($this->link);
        }
    }

    public function halt($message = '', $sql = '') {
        if(DEBUG) {
            $errormsg = "<b>MySQL Query : </b> $sql <br /><b> MySQL Error : </b>".$this->error()." <br /> <b>MySQL Errno : </b>".$this->errno()." <br /><b> Message : </b> $message <br />";
            echo '<div style="font-size:12px;text-align:left; border:1px solid #9cc9e0; padding:1px 4px;color:#000000;font-family:Arial, Helvetica,sans-serif;"><span>'.$errormsg.'</span></div>';
            exit;
        }
    }

    /**
    * 对字段两边加反引号，以保证数据库安全
    * @param $value 数组值
    */
    public function add_special_char(&$value) {
        if('*' == $value || false !== strpos($value, '(') || false !== strpos($value, '.') || false !== strpos ( $value, '`')) {
            //不处理包含* 或者 使用了sql方法。
        } else {
            $value = '`'.trim($value).'`';
        }
        return $value;
    }

    /**
    * 对字段值两边加引号，以保证数据库安全
    * @param $value 数组值
    * @param $key 数组key
    * @param $quotation
    */
    public function escape_string(&$value, $key='', $quotation = 1) {
        if ($quotation) {
            $q = '\'';
        } else {
            $q = '';
        }
        $value = $q.$value.$q;
        return $value;
    }
}
?>